Synthesis and characterization of structural and optical properties of heteroepitaxial brookite TiO₂ single crystalline films

Brookite titanium dioxide (b-TiO₂) films were successfully deposited on Y-stabilized ZrO₂ (110) substrates at different substrate temperatures (500–650 °C) by the metal organic chemical vapor deposition technique. The results of X-ray diffraction θ-2θ scan indicated that the b-TiO₂ film deposited at 550 °C had the best single crystalline quality, for which the heteroepitaxial relationship and the microstructure were identified by the X-ray diffraction Φ scan and high resolution transmission electron microscopy measurements. A schematic diagram was proposed to clarify the epitaxial growth mechanism. The composition, morphology and optical properties of the b-TiO₂ films have been investigated in detail.